ZMQHistoryManager made to work with testing KernelClient which has no history method

IPython/terminal/console/zmqhistory.py

@@ -1,93 +1,95
 """ ZMQ Kernel History accessor and manager. """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010-2011 The IPython Development Team.
 #
 #  Distributed under the terms of the BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from IPython.core.history import HistoryAccessorBase
 from IPython.utils.traitlets import Dict, List
 
 try:
     from queue import Empty  # Py 3
 except ImportError:
     from Queue import Empty  # Py 2
 
 class ZMQHistoryManager(HistoryAccessorBase):
     """History accessor and manager for ZMQ-based kernels"""
     input_hist_parsed = List([""])
     output_hist = Dict()
     dir_hist = List()
     output_hist_reprs = Dict()
 
     def __init__(self, client):
         """
         Class to load the command-line history from a ZMQ-based kernel,
         and access the history.
 
         Parameters
         ----------
 
         client: `IPython.kernel.KernelClient`
           The kernel client in order to request the history.
         """
         self.client = client
 
     def _load_history(self, raw=True, output=False, hist_access_type='range',
                       **kwargs):
         """
         Load the history over ZMQ from the kernel. Wraps the history
         messaging with loop to wait to get history results.
         """
+        history = []
+        if hasattr(self.client, "history"):
+            ## In tests, KernelClient may not have a history method
         msg_id = self.client.history(raw=raw, output=output, 
                                      hist_access_type=hist_access_type, 
                                      **kwargs)
-        history = []
         while True:
             try:
                 reply = self.client.get_shell_msg(timeout=1)
             except Empty:
                 break
             else:
                 if reply['parent_header'].get('msg_id') == msg_id:
                     history = reply['content'].get('history', [])
                     break
         return history
 
     def get_tail(self, n=10, raw=True, output=False, include_latest=False):
         return self._load_history(hist_access_type='tail', n=n, raw=raw, 
                                   output=output)
 
     def search(self, pattern="*", raw=True, search_raw=True,
                output=False, n=None, unique=False):
         return self._load_history(hist_access_type='search', pattern=pattern, 
                                   raw=raw, search_raw=search_raw, 
                                   output=output, n=n, unique=unique)
 
     def get_range(self, session, start=1, stop=None, raw=True,output=False):
         return self._load_history(hist_access_type='range', raw=raw, 
                                   output=output, start=start, stop=stop,
                                   session=session)
 
     def get_range_by_str(self, rangestr, raw=True, output=False):
         return self._load_history(hist_access_type='range', raw=raw, 
                                   output=output, rangestr=rangestr)
 
     def end_session(self):
         """
         Nothing to do for ZMQ-based histories.
         """
         pass
 
     def reset(self, new_session=True):
         """
         Nothing to do for ZMQ-based histories.
         """
         pass